This is not supported by the code generation, so it's a bit of a lie
to have them in the language in the first place. There's arguably not
even any use for constant records, list and tuples to begin with. So
this cleans this up everywhere for the sake of moving forward with the
alpha release.
This now reduces constants to:
- Integer
- ByteArray
- String
Anything else can be declared via a function anyway. We can revisit
this choice later.... or not.
Due to how PlutusData works it doesn't make sense
to allow user defined types to contain
functions.
```
type Foo {
bar: fn(Int) -> Int
}
```
The above definition will now return an error.